Spongy degeneration of the central nervous system

A rare genetic disorder affecting the central nervous system

Spongy degeneration of the central nervous system is a rare genetic disorder characterized by the degeneration of the central nervous system (CNS) leading to the formation of spongy tissue. This condition is also known as Canavan disease, named after the researcher who first described it. It primarily affects infants and young children, leading to severe neurological impairment.

Pathophysiology

The disease is caused by mutations in the ASPA gene, which encodes the enzyme aspartoacylase. This enzyme is responsible for breaking down N-acetylaspartic acid (NAA) in the brain. In the absence of functional aspartoacylase, NAA accumulates, leading to the formation of spongy tissue in the brain's white matter.

U fibers in the brain

The accumulation of NAA disrupts the normal development and maintenance of myelin, the protective sheath surrounding nerve fibers. This disruption results in the characteristic spongy degeneration seen in affected individuals.

Clinical Features

Symptoms of spongy degeneration of the CNS typically appear in early infancy. Affected infants may exhibit poor muscle tone (hypotonia), developmental delays, and an enlarged head (macrocephaly). As the disease progresses, children may experience seizures, feeding difficulties, and loss of previously acquired skills.

Diagnosis

Diagnosis is often based on clinical presentation and confirmed through genetic testing for mutations in the ASPA gene. Magnetic resonance imaging (MRI) of the brain can reveal the characteristic spongy degeneration and white matter changes.

Amniocentesis procedure

Prenatal diagnosis is possible through amniocentesis or chorionic villus sampling if there is a known family history of the disease.

Treatment

Currently, there is no cure for spongy degeneration of the CNS. Treatment is supportive and focuses on managing symptoms and improving quality of life. This may include physical therapy, nutritional support, and medications to control seizures.

Gene therapy research

Research into potential treatments, such as gene therapy, is ongoing. Gene therapy aims to deliver a functional copy of the ASPA gene to affected cells, potentially correcting the underlying enzyme deficiency.

Prognosis

The prognosis for individuals with spongy degeneration of the CNS is generally poor. Most affected children do not survive beyond early childhood, although the severity and progression of the disease can vary.

Related pages

• Genetic disorder
• Central nervous system
• Myelin
• Gene therapy